Water resistant fibrous articles and their manufacture



nish board.

structurally strong mass.

Patented June 9, 1931 UNITED STATES PATENT OFFICE DILLON 1?. SMITH, OF PENSACOLA, FLORIDA, AND ERNEST J. PIE'PER AND CLARENCE G.

VOGT, 0F LANCASTER, PENNSYLVANIA, ASSIGNOR-S TO ARMSTRONG CORK COM- PANY, 0F LANCASTER, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA WATER RESISTANT FIIBROUS ARTICLES AND THEIR MANUFACTURE No Drawing.

The

present invention relates to water resistant brous articles and their manufacture,

and more especially to an artificial fiber board of the type which we have designated as var- In this board the fibers are coated or sized with a varnish. Preferably, suflicient varnish is employed so that it acts not only as a sizing, but also as a binder holding the fibers together in a compacted, hard, In general, such board differs from the usual insulating board sold under various trade names and which consists of loosely matted or felted cellulose fibers and containing a considerable air space. Such insulating board, because of its open porous construction,will readily absorb water. The board herein described is water repellent as a whole, and the varnish binder forms a substantially continuous binder for the fibers so that the board is not-a porous board like the ordinary insulating board, but is a rather hard dense board. Since the board does not have the large volume of inter-fiber air spaces characteristic of insulating boards, it does not have the heat insulating qualities of such insulating boards. On the other hand, it is not water absorbent and may be used in exterior work where it is exposed to the weather.

In making our varnish board, a varnish is put onto the fibers, preferably by forming the varnish in the fibrous pulp from which the board is made. and coats the fibers, thus waterproofing the individual fibers. It holds the fibers together into a hard dense structure which is water repellent. The board is structurally strong and it may be. cut and otherwise handled similarly to lumber.

We will now describe the preferred process of making such board, first with particular reference to the, use of fibrous material containing, in itself, a resin. A pulp of this character may be formed by shredding or grinding resinous woods, such as the pines, spruces, etc. An available supply of such wood materialis the refuse from plants which extract rosin from light wood of the yellow or Southern pine. The light wood is the stumpage and logs of the yellow or Southern long to in thickness.

The varnish saturates 'Application filed January 9, 1929. Serial No. 331,385.

leaf pine which has been exposed for several is rich in rosin and is extracted to recover the rosin and turpentine. The wood is first chipped into chips generally about from to 1 A long, from 5 to 1 wide, and from The chips are first steam distilled to extract turpentine. They are then treated with naphtha or gasoline to dissolve the rosin. The gasoline or naphtha solution is later evaporated and the rosin recovered. This extraction process does not extract all of the rosin from the chips. It leaves on the average about 5% to 6% of rosin in the chips. These chips are at the present time a waste product and are usually burned.

In making our fiber board from such pine chips, the chips are shredded or. ground, preferably with water, either hot or cold, to form a pulp. Any suitable shredding or grinding machinery may be used for this purpose. In the procedure now being described, noscaustic is added to the water, so that the residual rosin will be preserved in and upon the fibers.

A suitable quantity of a siccative oil, such aslinseed oil, either alone or dissolved in some solvent, such as naphtha, is added and beaten into the pulp. The oil or mixtureof oil and solvent is non-miscible in the water of the pulp and will be deposited upon the wood fibers. The oil which is deposited upon the fibers, and the rosin in the fibers, furnish the materials from which a varnish is formed in the completed board. After the oil has been thus deposited uniformly over the fibers of the pulpy mass, the excess water is removed and the fibers are felted into a board or other desired shape in theusual way for making such articles. The wet board is dried at 180 to 400 Fahrenheit. During the drying, the rosin and drying oil interact to form a Water resistant film over the surface of the fibers. If a consolidating pressure is applied during the drying, a dense board not pervious to water may be produced. It is preferred to compress the board during the drying operation to form a board of this character. However, by regulating the pressure and the amount of varnish forming materials, a board may be formed 'which is somewhat porous, although the individual fibers thereof are coated with the varnishand thus rendered resistant to the absorption of the water by the cellulose and the consequent swelling thereof.

The residual rosin in the waste chi s from the rosin extracting plants may be ot erwise combined with the drying oil to form the waterproof sizing or binder. For example, the pine chips containing the residual rosin left after the naphtha extraction may be shredded and cooked and round with sodium hydroxide or lime, Whi rosin completely or partially into a resinate. A suitable precipitant, such as aluminum sulphate, aluminum chloride, calcium chloride, etc., may then 'be added to the pulp to precipitate the rosin as an aluminum resinate or other insoluble size n on the fibers. A drying oil can then be ad ed and the process carried out by forming the board and heating it so as to form the varnish upon the fibers. In case the residual rosin in the chips is not sufiicient to produce enough varnish, rosin dissolved in' a solvent, such as naphtha, or a resinate, such as sodium resinate, may be added to the pulp to furnish an additional supply of the rosin constituent of the varnish.

While the rosin-containing pine chips are a preferred raw material because they contain rosin which would otherwise be unrecovable, and because they are a cheap source of already chipped material, other fibrous materials may be used in our process. Wood fiber, which does not contain a resin, may be used and the resin supplied to it. For example, an ordinary wood pulp may be suspended in water and a resin supplied to it in the form of sodium resinate, which is thoroughly mixed with the pulp. A precipitant, such as aluminum sulphate, may e added to convert the soluble resinate in and upon the wood fibers into an insoluble resinate or size, or, if desired, a resinate which is insoluble in water or rosin or other resin, may be dissolved in some solvent, such as naphtha, and beaten with the wood pulp.

The naphtha solution, which is not miscible in the water, will tend to attach itself to and spread over the fibers, thus evenly applying the resin or resinate to them. The expressions resin bearing fibrous material or resin bearing fibers are intended to include not only materials containing resin originally existing in the fibers, but also fibrous materials to which resin has been supplied.

Then, a drying oil, such as linseed oil, alone or in a solvent to thin it, is thoroughly beaten with the pulp and the oil evenly distributed over the fibers. The excess water is then removed by suction or other means and the pulp made into thedesired articles, such as board, which is dried at from 180 to 400 Fahrenheit. The drying causes the varnishwill convert the and a resin and beating such solution into the pulp formed by the fiber suspended in water. v

If desired, a varnish may be made in the usual way, such as by boiling an oil and resin together to give it body and the varnish thinned in a solvent and thus applied to a pulp. It is much preferred, however, to desit the varnish-making materials upon the bers and to thicken or give the body to the varnish during the drying and heating of the article.

In the making of a varnish by boiling the resin and oil together, the materials become polymerized or coagulated, which gives the body to the varnish. In case such fullbodied varnish is used, more solvent is required to carry it into the fibers. When, however, the unpolymerized varnish constituents are added, less solvent is required'to distribute them in the pulp. Moreover, whenthe unthickened varnish-making materials are carried into the pul they can be better distributed over the fi rs than if an attempt were made to add already formed varnish.

In this way the varnish constituents in their thinnest and most readily applied form coat and saturate the fibers, and the thickening does not occur until aften-this distribution has taken place. We have found that an oil or a solution of an oil in a solvent which is non-miscible with water, or a resin in a solvent which is non-miscible with water, when beaten into a pulp formed of the fibers suspended in water, tend to separate out from the water emulsion so formed and to distribute themselves uniformly over the surface of the fiber. This property of solutions nonmiscible in water of coating the fibers is described in our copending application, Serial No. 236,359, filed November 28, 1927.

While various varnish-making resins may be used, such as kauri gum, fossil gum, or copal, it is preferred to use rosin because of its cheapness. Various siccative oils or oleaginous materials may be used as the oily constituent of the varnish. The expression siccative oils is intended to cover such oils as linseed oil and china wood oil, which are known as drying oils, and also the semi-drying oils, such as soy bean oil, fish oil, etc. While it is preferred to use a siccative oil as the oily constituent of the varnish, other siccative oily materials may be used, such, for example, as stearine pitch. Various solvents, preferably solvent-s which are non-miscible iu the water, such as naphtha, gasoline, etc., may be used, if desired, to carry the varnish or varnish-forming constituents into the pulp and distribute them on the fibers. During the drying of the articles the solvents are evaporated and may be recovered.

The heating and drying of the board will usually sufficiently harden it so that it can be handled upon cooling. The siccative oleaginous materials in the varnish, however, continue to slowly oxidize in the board. Apparently, the incomplete oxidation and the capacity to take up more oxidation, tends to give more life to the board, somewhat, as we believe, analogous to that of a paint film which is not fully oxidized.

The physical characteristics of the board may be varied by adjusting the amount of varnish formed and the pressure under which the article, such as the board, is made. If but a small amount of varnish is formed, such,

i or example, as by using the extracted pine 1 chips containing 5% to 6% of rosin and a relatively small amount of oil with them, a board of an open fibrous construction, somewhat resembling the insulating boards now on the market, may be produced, but having.

superior resistance against swelling due to the protection against water afforded to the fibers by their varnish coatings. Ordinarily, however, the amount of varnish and pressure used in making the board will be sufiicient to form a solid and rather non-porous board or other article. Such solid board can be used for exterior work as it will shed moisture when exposed to the weather. The board also has a high structural strength due to the varnish solidly binding together the fibers. It can, therefore, be used for purposes for which the ordinary insulating boards are unsuitable because of their lack of structural strength.

The invention has been described with particular reference to the manufacture of artificial board, but other fibrous articles may be produced, such, for example, as substitutes for various articles of furniture and wooden ware articles now made from natural lumber.

\Vhile we have described the preferred embodiments of our invention, it is to be understood that the invention may be otherwise embodied and practiced within its scope as defined in the following claims.

lVe claim:

1. The process of making fibrous articles, which comprises forming a water-containing pulp of resin bearing fibrous material, adding a siccative oleaginous material to the pulp and distributing it over the resin-containing fibers. forming the articles from such pulp, and drying and heating them so as to cause the resin and oil to combine and form a varnish in situ on the fibers.

2. The process of making fibrous articles from the refuse chips from rosin extraction plants, such chips containing residual rosin, whichcomprises forming a pulp from the chips, adding a siccative oil to the pulp, forming the articles from the pulp, and drying them so as to form a varnish in situ upon the fibers.

3. The process of making fibrous articles from the refuse chips from rosin extracting plants, such chips containing residual rosin, which comprises forming a pulp from the chips, adding a siccative oleaginous material to the pulp, forming the articles from the pulp, and treating them so as to form a varnish in situ upon the fibers.

' 4. The process of making fibrous articles, which comprises forming a Water-containing fibrous pulp having resin-bearing fibers, adding a siccative oily material in a liquid condition to the pulp and beating the pulp so as to distribute it over the resin-bearing fibers, forming, articles from such pulp, and drying and heating them.

5. The process of making fibrous articles, which comprises forming a water-containing fibrous pulp, distributing normally liquid varnish-making constituents on the fibers of such pulp while cold, forming the articles from the pulp, and treating them so as to combine the varnish-making constituents and form a varnish in situ on the fibers.

6. The process of making fibrous articles,

fibrous pulp, distributing an oil varnish liquid at normal room temperatures on the fibers of such pulp, forming the articles from the pulp, and drying and heating them.

7. The process of making varnish-bonded fibrous articles, which com rises forming a water-containing fibrous pu p, adding to the pulp material which will become distributed over the fibers in liquid form at normal temperatures and form an oil varnish thereon, and beating the mass to eliect such distribution, forming the articles from the pulp, and drying and heating them.

8. A fibrous article containing the wood fibers of the residual-r0sin-containing chips from rosin-extracting plants, and having said fibers bonded with a varnish formed at least in part from the residual rosin of 10. The process of making varnish-bonded f fibrous articles, which comprises forming a water-containing fibrous pulp, adding to the pulp varnish-making material liquid at normal room temperatures which will become distributed over the fibers, beating the mass to effect such distribution; forming the article from the thus-treated pulp, and dryin and heating the article to cause the varnishorm-.

- an added siccative oleaginous material In testimony whereof we have hereunto set our hands.

DILLON F. SMITH. ERNEST J. PIEPER. CLARENCE C. VOGT. 

